Developing process

ABSTRACT

A PROCESS FOR DEVELOPING A SILVER HALIDE PHOTOGRPAHIC LIGHT-SENSTIVE MATERIAL WHICH COMPRISES DEVELOPING THE LIGHT-SENSITIVE MATERIAL IN THE PRESENCE OF A COMPOUND REPRESENTED BY THE FOLLOWING GENERAL FORMULA:   2-(R-S-CH2-CO-NH-),4-R2,5-R1-THIAZOLE   WHEREIN R REPRESENTS AN UNSUBSTITUTED OR SUBSTITUTED ALKYL GROUP OF 1-5 CARBON ATOMS, ARALKYL GROUP OF 1-5 CARBON ATOMS, OR ARYL GROUP, AND R1 AND R2 EACH REPRESENTS A HYDROGEN ATOM OR AN ALKYL GROUP OF 1-5 CARBON ATOMS, SAID R1 AND R2 ALSO CAPABLE OF FORMING AN UNSATURATED CONDENSED RING OF 5-6 CARBON ATOMS, WHICH MAY BE FURTHER SUBSITUTED BY AN ALKYL GROUP OF 1-5 CARBON ATOMS.

Jul 4, 1972 YOO llJlMA ETAL 3,674,491

DEVELOPING PROCESS Filed NOV. 30, 1970 FIVE MINUTES I FOUR MINUTES 2 THREE MINUTES DENSITY AMOUNT OF EXPOSURE DENSITY 2 AMOUNT OF EXPOSURE SIX MINUTES 3 2- FOUR MINUTES i L /TWO MINUTES U i 2 3 4 INVENTORS AMOUNT OF EXPOSURE YOO "MA ISAO- SHIMAMURA TOKIHARU KONDO HARUHIKE IWANO United States Patent O 3,674,491 DEVELOPING PROCESS Yoo Iijima, Isao Shimamura, Tokiharu Kondo, and Hamhike Iwano, Kanagawa, Japan, assignors to Fuji Photo Film Co., Ltd., Kanagawa, Japan Filed Nov. 30, 1970, Ser. No. 93,672 Claims priority, application Japan, Nov. 29, 1969, 44/95, 185 Int. Cl. G03c 5/30 US. Cl. 96-663 16 Claims ABSTRACT OF THE DISCLOSURE A process for developing a silver halide photographic light-sensitive material which comprises developing the light-sensitive material in the presence of a compound represented by the following general formula:

condensed ring of 5-6 carbon atoms, which may be further substituted by an alkyl group of 1-5 carbon atoms.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to a process for developing silver halide photographic light-sensitive materials and more particularly to a development process for reducing the gamma of a photographic image.

Description of the prior art It is very important to control the gradation of the gamma of an image obtained when developing with a silver halide photographic material. It is also important to reduce the grain size of the developed silver particles. Various types of fine grain developing solutions have been known. For instance, some of them are disclosed in the specifications of US. Pats. Nos. 2,113,312; 2,164,280; 2,311,428 and 2,840,471 and the specification of British Pat. No. 723,286. However, the resolving power and granularity of the images obtained by these known finegrain developers still remain insufiicient for micro-filming insofar as ordinary photographic films or papers, which are not designed for micro-filming, are concerned. A lightsensitive material for micro-filming is commercially available as a material having a high resolving power and good granularity. Although this material has excellent resolving power and granularity, the gamma of the processed image is too high for recording of tonal scenery.

Therefore, it would be quite profitable to develop a method for obtaining a micro-image having soft gradation, high resolving power and reduced granularity by employing a micro-film which gives hard tone with conventional development. Various investigations have been conducted for finding such a developing process suitable for such purposes. In this regard, there is known, for example, French Pat. No. 1,495,935. In this patent, the soft tone is obtained by pre-treating a photographic film with an aqueous solution of a noble metal salt before development. In Japanese patent publication No. 14,510/69 (Japanese Pat. No. 561,153), the image tone of a high gamma photographic film is softened by developing it by a conventional soft tone developing solution and fixing 3,674,491 Patented July 4, 1972 the film with a fixing solution containing an oxidizing agent. This procedure, however, has the shortcoming of a decreased fixing rate.

In this process, the fixing time must be strictly controlled and the life of fixing solution is reduced, since the fixer contains an oxidizing agent, which makes the treatment of the process diflicult. On the other hand, in the process of the French Pat. No. 1,495,935, an inexpensive noble metal is used and an additional processing step is required, which makes the developing process complicated. Hence, it is very difficult to obtain a soft tone image using a high gamma photographic film by only employing the device in a conventional development procedure.

Furthermore, a developing solution containing 1- phenyl-3-pyrazolidone as the sole developing agent can be used in order to reduce the gamma of the image but it is accompanied by low sensitivity. In addition, it is very easily exhausted by processing small quantities of films. On the other hand, a developing solution containing N- methyl-p-aminophenol may have a high sensitivity but it is not effective for obtaining a soft tone image. Moreover, a developing solution combining suitable amounts of lphenyl-3-pyrazolidone and N-methyl-p-aminophenol may exhibit high sensitivity and provide a considerably soft tone image but is easily exhausted. Furthermore, a developing solution containing a proper amount of l-phenyl- 3-pyrazolidone, N methyl p arninophenol and hydroquinone may have a high sensitivity and is not easily exhausted but it is imposible to obtain good soft tone images by using such a developing solution.

As mentioned above, many attempts have been made to solve the problem but none has every fully satisfied the requirements for recording tonal objects on a microfilm or paper. That is, they never provide sufficient sensitivity for printing work, gradation soft enough for recording the tonal scenery, or good resistivity to exhaustion.

SUMMARY OF THE INVENTION It is, therefore, the primary object of the present invention to provide a process for producing soft tone images without any loss of granularity and resolving power by using silver halide photographic recording materials of fine grain, high contrast and relatively low sensitive type.

Accordingly, the object of this invention can be achieved by developing high contrast silver halide photographic light-sensitive material in the presence of a compound represented by the following formula:

wherein R represents an unsubstituted or substituted alkyl group of 1-5 carbon atoms, aralkyl group of l-5 carbon atoms or aryl group and R and R each represents a hydrogen atom or an alkyl group of l-5 carbon atoms, said R and R also capable of forming an unsaturated condensed ring of 5-6 carbon atoms, which may be further substituted by an alkyl group of 1-5 carbon atoms.

Illustrative of the compounds shown above to be employed in the present invention follow,

*Any substituent will suflice, providing however, it does not detract from the goals of the present invention.

Compound M.P., C.

--NH 0 on; s on,

NH0 0 ems 0211.

-Nnc 0 ems Q VNHC o ems em I -Nnc o ems 02H;

I NHC0CHzS- N on /S Nneoemsenr, N

These compounds may be synthesized generally by the following process:

DETAILED DESCRIPTION OF THE INVENTION Synthesis example Synthesis of 2 (S ethylglycolamido)benzothiazole (Compound )34 g. of Z-aminobenzothiazole was dis.- solved in 120 ml. of anhydrous pyridine. Subsequently, an ether solution of 38.5 g. of chloroacetyl chloride was added dropwise to the solution with stirring while cooling the solution to temperatures lower than 5 C. Thereafter, the mixture was further stirred for 2 hours at room temperature to complete the reaction. Then the solution was poured into 2 liters of water and the precipitated crystals were recovered. 36 g. of crude 2-chloroacetamidebenzothiazole having a melting point of 160-163 C., was obtained.

2.8 g. of potassium hydroxide was dissolved into about 70 ml. of ethanol. After adding to the solution 11.32 g. of 2-chloroacetamido-benzothiazole, as prepared above, the mixture was refluxed for 4 hours under heating. The reaction product was concentrated under a reduced pressure and dried. The product was then extracted with benzene. After distilling the benzene away, the residue was recrystallized from 50% alcohol to give 5 g. of 2-(S- ethylglycolamido)benzothiazole having a melting point of 128-129 C.

By following the same procedure as illustrated above using methyl mercaptan instead of ethyl rnercaptan, 2-(S- methylthioglycolamido)benzothiazole (Compound 4) was obtained. Also, by using thiophenol instead of ethyl mercaptan in the above procedure, Z-(S-phenylthioglycolamido)benzothiazole (Compound 6) was obtained. Furthermore, by using Z-aminothiazole instead of Z-aminobenzothiazole, the corresponding thiazole derivatives (Compounds l-3) were obtained. Also, by using 2-amino- S-methyl-benzothiazole instead of 2-amino-benzothiazole in the above procedure, Z-(S-methylthioglycolamido)-5- methyl-benzothiazole (Compound .7 was obtained.

The compounds of this invention can be applied to generally high contrast silver halide photographic recording materials of fine grain and relatively low sensitivity.

Various organic anti-foggans, such as 6-nitrobenzimidazole, benzotriazole, or 1 phenyl-S-mercaptoterazole are known. The addition of large amounts of-such compounds to the developer will also lower the gamma, but sincethe sensitivity iszzgreatly reduced, the use of the compounds for this purpose is not practicable.

The addition of a large amount of other developing inhibitors, such as potassium bromide or potassium iodide, willalso lower the gamma, butthese compounds are impracticable for the same reason as indicated above,

The developing solution containing the above compound of the present invention contains at leastone developing agent, such as hydroquinone, 1-phenyl-3-pyrazolidone, N methyl-p-amino-phenol, etc. Furthermore, it contain one or more antioxidants, such as sodium sulfite, ascorbic acid, etc.; a salt such as sodium sulfate, a pH ad.- justing agent and a bulfering agent, such as boric acid, borax, sodium hydroxide, sodium carbonate and sodium phosphate, and the like.

In order to enhance the softening, potassium bromide or potassium iodidemay be used together with the compound of=this invention. Further, for reducing the formation of fogs, other organic anti-foggants may be used together with the compounds of the present invention. In some cases, an aldehyde such as formalin or glutaraldehyde or an organic solvent such as triethylene glycol and hexylene glycol may be added. Still further, a developing accelerator such as an amine or a polyethylene glycol may also be used together with the compounds of this invention.

In case of adding the compound of this invention to a developing solution, the amount of the compound. added is usually 1 mg. to 10 g. per liter of developing solution, although the amount depends on the composition of the developing solution, the developing temperature, and the nature of the light-sensitive material. A preferred range is 30-100 mg./liter of solution. When not employed in a developer, the concentration of the compound of the present invention may range from 1 mg.-10 g. and preferably 50-200 mg./kg. of emulsion.

The compound of this invention shows the effective reduction of contrast, not only when the compound is added to a developing solution but also when it is incorporated in a photographic light-sensitive material. Therefore, the use of the compound is not limited to a developing composition.

A better understanding of the present invention will be attained from the following examples, which are merely intended to be illustrative and not limitative of the present invention:

EXAMPLE 1 A micro-film prepared by coating a film support with a fine grain silver chlorobromide gelatin emulsion was exposed by means of a sensitometer and developed by one of the following three kinds of developing solutions, labelled A, B and C.

Developing Solution A: G. N-methyl-p-aminophenol sulfate 1.0 Sodium sulfite 75 Hydroquinone 9.0 Sodium carbonate mono-hydrate 30 Potassium bromide 5.0 Water added to make 1 liter.

Developing Solution B: G. N-methyl-p-aminophenol sulfate 0.5 Sodium sulfite 10 Nabox 1 2.0 Water added to make 1 liter.

1 Sodium metaborate.

Developing Solution C: G. 1-phenyl-3-pyrazolidone 4.0 N-methyl-p-amonophenol sulfate 1.0 Sodium sulfite 100 Sodium carbonate mono-hydrate 30 Potassium bromide 5.0 Compound Water added to make 1 liter.

The developing solution A is a known high contrast developing solution.

The developing solution B is a known low contrast developing solution.

The developing solution C is a low contrast developing solution of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The characteristic curves of the images obtained by developing the microfilms with the above three kinds of developing solutions are shown in FIGS. 1-3 of the accompanying drawings, in which:

FIG. 1 shows the characteristic curves of the image obtained by processing the microfilm with the high contrast developing solution A;

FIG. 2 shows the characteristic curves of the image obtained by developing the microfilm with the known low contrast developing solution B, and

FIG. 3 shows the characteristic curves of the image obtained by the developing solution of the present invention.

As shown in the above results, the high gamma was obtained in the case of using the developing solution A, as shown in FIG. 1. On the other hand, developing solution B lowered the gamma as compared to image developing solution A as shown in FIG. 2. Still, the gamma was too high. When, however, the developing solution C of this invention was employed, a soft tone image as shown in FIG. 3 was obtained.

EXAMPLE 2 A microfilm prepared by coating a support with a fine grain silver chlorobromide gelatin emulsion was exposed by a sensitometer and then developed at 27 C., by the developing solution C in Example 1. For the sake of comparison, a developing solution D having the same composition as the developing solution C of this invention (without the presence of the compound of this invention) and also the developing solutions E, F, G and H having the same condition as developing solution C were prepared. However, the following Compounds 8, 9, l0 and 11 outside the scope of this invention, were used, respectively, instead of the compounds of this invention. Similar developing procedures were conducted.

The photographic properties of the images obtained by the developing processings are shown in the following table:

Photographic property Developing solution Compound (amount) Fog Gamma C Compound 5 (50 mg.l1.) 0. 10 0. 64 D 0. l1 1. 08 0. l2 0. 96 0. 12 1.05 0. 11 0. 97 0. 12 1. 04 0. 10 0. 70

Compound 8:

l 1* S H R l N Compound 9:

S H N Compound 10:

S H N Compound 11:

As shown in the above results, only in the case of developing solution C containing the Compound 5 of this invention, was a low gamma value attained. In the cases of employing developing solutions containing the Compounds 8-11 (which were outside the scope of this invention) such low gamma values could not be obtained.

EXAMPLE 3 A microfilm prepared by coating a support with a fine grain silver chlorobromide gelatin emulsion was exposed by means of a sensitometer and developed at 27 C., with developing solutions I and K having the same composition as developing solution C except that the Compounds 6 and 7 were used instead of the Compound 5.

The photographic properties of the images thus obtained are shown in the following table:

Photographic property Developing solution Compound (amount) Fog Gamma D 0.11 1. 08 J Compound 6 (50 rug/i.) 0.10 0. 68 K Compound 7 (50 mg.fl.) 0.10 0. 65

As indicated in the results above, soft tone development could be attained by the addition of the Compounds 6 or 7 of this invention.

EXAMPLE 4 A microfilm prepared by coating a support with a fine grain silver chlorobromide gelatin emulsion was exposed by means of a sensitometer and developed by developing solution L of this invention at 27 C.

For the sake of comparison, the same developing procedure was followed using the developing solution M having the same composition as the developing solution L, except that it did not contain the Compound 2 of this invention.

Developing Solution L:

N-methyl-p-aminophenol sulfate g 8.0 sodium sulfite g 125 sodium carbonate mono-hydrate -g 6.7 Potassium bromide g 2.5 Compound 2 mg 50 Water added to make, to 1 liter.

The photographic properties of the images thus obtained are shown in the following table:

Ihotographic property Developing Added compound solution (addition amount) Fog Gamma L Compound 2 (5O ml.[1.) 0.11 0. 67 M 0. 13 1. 42

EXAMPLE 5 Developing Solution N:

1-pheny1-3-pyrazolidone N-methyl-p-aminophenol sulfate Sodium sulfite Sodium carbonate mono-hydrate 30 Hydroquinone 2.0 Potassium bromide 5.0 Compound 5 mg 50 Water added to make the whole volume to 1 liter.

The photographic properties of the images obtained by the development are shown in the following table:

Photographic property Developing solution Compound (amount) Fog Gamma N Compound 5 (100 mg.ll.)- 0.10 0. 66 O 0. 12 1. 3s

A 1 phenyl-S-pyrazolidone/N-methyl-p-aminophenol/ hydroquinone type developing solution has a higher processing function than a 1-phenyl-3-pyrazo1idone/N-methylp-aminophenol type developing solution but shows undesirably high gamma characteristics. However, by adding the Compound 5 of this invention to the'former type developing solution, soft tone developments can be attained. Furthermore, the developing power becomes higher, as shown in the above table.

'When all of those compounds disclosed in col. 3 of the present application are substituted with methyl or ethyl radicals as in Compound 7, identical and even better results (in some cases) are observed.

Although the present invention has been adequately described in the foregoing specification and examples included therein, it is readily apparent that various modifications and changes may be made without departing from the intended scope thereof.

What is claimed is:

1. A process for developing a silver halide photographic light-sensitive material which comprises developing the light-sensitive material in the presence of a compound represented by the following general formula:

NHC 0 CHzS-R R2 wherein R represents an unsubstituted or substituted alkyl group of 1-5 carbon atoms, aralkyl group of l-S carbon atoms, or aryl group, and R and R each represents a hydrogen atom or an alkyl group of 1-5 carbon atoms, said R and R also capable of forming an unsaturated condensed ring of 5-6 carbon atoms, which may be further substituted by an alkyl group of 1-5 carbon atoms.

2. The process of claim 1 wherein said compound is contained in a developer.

3. The process of claim 2 wherein said developer is a developer for forming soft tone images on microfilm.

4. The process of claim 1 wherein said compound is:

N 5. The process of claim 1 wherein said compound is:

6. The process of claim 1 wherein said compound is:

s -NHCOCH1SCH 7. The process of claim 1 wherein said compound is:

s t NHCOCH2S 8. The process of claim 1 whereinsaid compound is: t

NHOOCH2SCH3 9. The process of claim 1 wherein said compound is:

NHCOCH2S I 10. The process of claim 1 wherein said compound is:

10 11. The process of claim 2 wherein the concentration References Cited of said compound ranges from 1 mg.-l g. per liter of developing Solution. UNITED STATES PATENTS 12. The process of claim 11 wherein the concentration 3,046,130 7/1962 Dersch et a1. 96-663 of said compound ranges from 30-100 mg. per liter of 3,084 4/1963 Dersch et aL 96 66.3 developing solution.

13. The process of claim 1 wherein a photographic 3342596 9/1967 Graham 96 66'3 emulsion containing said compound is employed. 3,502,467 3/1970 Becker 14. The process of claim 13 wherein the concentration 3,305,362 2/1967 Riester et a1. 96-66 of said compound in said emulsion ranges from 1 mg. 10 g. per kg. of emulsion. NORMAN G. TORCHIN, Primary Examiner 15. The process of claim 14 wherein the concentration of said compound ranges from -200 mg./kg. of emul- KIMLIN, Asslstant Exammer sion.

16. The silver halide photographic light-sensitive mate- 15 rial developed by the process of claim 1. 9666,

US. Cl. X.R. 

